Photo 1: EF 24-70mm f/2.8L II USM
Photo 3: EF 28mm f/2.8 IS USM
Photo 2: EF 24mm f/2.8 IS USM
I. EF 24-70mm f/2.8L II USM (Photo 1)
Developed as the successor to the EF 24-70mm f/2.8L USM, this lens is a large-aperture L-series standard zoom lens offering superb image quality. Users have long prized the EF 24-70mm f/2.8L USM since its release in 2002 as a high-performance standard zoom lens. During these nine years, however, demands have mounted for even better image quality and greater durability as the market has gone completely digital and the number of photos taken soared.
The EF 24-70mm f/2.8L II USM was developed with the objective of improving the image quality at all zoom positions and across the entire frame as well as mitigating performance degradation caused by years of use (i.e., improving the lens's durability and reliability). With these improvements, the EF 24-70mm f/2.8L II USM is well positioned as a daily-use lens for the digital age that meets both market demands and tougher usage conditions.
The following sections detail the main features of this lens.
Feature 1 — More compact and remarkably better image quality
The two biggest advancements of the EF 24-70mm f/2.8L II USM are its shorter length and its generally improved image quality.
To accomplish these two aims, we completely changed the past model's optical configuration. We switched from the previous six-group zoom configuration, which reaches its minimum length at the maximum telephoto angle, to a four-group zoom configuration, which reaches its minimum length at the maximum wide angle. This change enabled us to make the lens much more compact, reducing its overall length to 113 millimeters, 10.5 millimeters shorter than the previous model. The lens also features an inner-focusing system that focuses by moving the second lens group.
The lens's construction consists of 18 elements in 13 groups (Figure 1). To minimize chromatic aberrations at all zoom positions and across the entire frame, we positioned one UD lens element in both the third and fourth lens groups and one super UD lens element in the fourth lens group. Furthermore, by placing an aspherical lens element in the second, third, and fourth lens groups, the lens is able to render images with outstanding clarity and extremely high resolution at all zoom positions and from the center of the frame to the very edges. Thanks to these lens-construction innovations, the lens's image quality vastly outperforms that of the previous model (Figure 2).
Advanced simulation technology was used to optimize the lens coating, which provides excellent color balance as well as minimal flaring and ghosting that commonly occurs with digital cameras. We also treated the front lens group 1 (R1 face) and the rear lens (R2 face), which are exposed to the open air, with a fluorine coating.
- How to read MTF charts
- Bold lines: 10 lp/mm, fine lines: 30 lp/mm. Black lines are the MTF characteristics at full aperture; the blue lines at f/8. Solid lines represent sagittal MTF and the broken lines represent meridional MTF.
Feature 2 — Improved reliability and durability
Along with the optical system modifications, we redesigned the construction of the lens barrel components to handle even tougher usage conditions than were envisioned for the previous model. This redesign has greatly improved the lens's durability and reliability.
To improve the lens's reliability, we assumed various kinds of impacts to the lens. Using precision simulation technology, we characterized and analyzed the locations of possible impact in order to create a mechanical construction that is even sturdier than before. Part of this work entailed designing and incorporating, within very tight space constraints, large components even stronger than in the past to reinforce high-stress areas.
An example of the lens's durability improvements is the very resilient support structure, previously only used in super telephoto lenses, located in the lens-barrel drive mechanism for the focusing lens group. We also developed a compact zoom mechanism that maintains with great accuracy the relative positions of the lens groups.
While it is impossible to prevent sliding parts from wearing over years of use, the previously mentioned focus mechanism and zoom mechanism have been designed to maintain positioning within the optical system with sufficiently high precision for a bright f/2.8 lens even as various components wear over time.
And to protect against water and dust intrusion while shooting in harsh conditions, waterproofing and dustproofing has been applied around all controls and moving parts including the mount, the switch panel, the zoom ring, the focusing ring, the zoom ring lock lever, and the zooming extension tube (Figure 3).
Feature 3 — Better AF accuracy
The AF system consists of the inner-focusing system, a ring USM drive unit, a high-speed CPU, and an optimized AF algorithm. AF accuracy has been boosted with the inclusion of a sensor with higher resolution than on the previous model. Furthermore, the lens's focusing control and aperture control have been improved to meet the demands of movie shooting.
Feature 4 — Improved usability
The lens, which has an overall length of 113 millimeters and weighs 805 grams, has been made easier to handle by shrinking its overall length by 10.5 millimeters and shedding 145 grams from the previous model (which had an overall length of 123.5 millimeters and weighed 950 grams).
The concept of the exterior design was to provide a high-end feel for the lens while prioritizing operability. Working from this concept, we formed the lens silhouette and molding for maximum operational comfort. Similarly, the focus ring and zoom ring were designed for better control. Finally, the exterior surface was treated with a top-quality leather-texture coating to give the lens a luxurious feel.
A zoom ring lock lever has been added to prevent the zoom from extending out while carrying the lens mounted to a strap-held camera. The lens comes with the petal-shaped EW-88C (Photo 4) hood that attaches with a two-pronged bayonet mount and includes a lock mechanism. The hood's inner surface has been given a flocking treatment for excellent anti-reflective performance.
The EF 24-70mm f/2.8L II USM is a high-performance standard zoom lens that maintains the features of the previous model — namely, superb image quality, fast autofocusing, full-time manual focusing, and excellent operability — with significant advances for higher image quality, better durability and reliability, and improved usability.
Users of APS-C sensor cameras can enjoy the everyday utility of the lens's equivalent focal length of 38 to 112 millimeters.
As an entry into the world of L-series lenses, this single lens offers a universe of creative expressions that stir the imagination. Try it once, and it is sure to be a lifetime favorite.
|Model||EF 24-70mm f/2.8L II USM||EF 24-70mm f/2.8L USM|
|Lens construction||18 elements in 13 groups||16 elements in 13 groups|
|Aspherical lens elements||3||2|
|Super UD / UD elements||1 / 2||0 / 1|
|Aperture blades||9 (circular)||8 (circular)|
|Min. focusing distance||0.38 m||0.38 m|
|Filter size||82 mm||77 mm|
|Max. diameter||88.5 mm||83.2 mm|
|Overall length||113 mm||123.5 mm|
|Weight||~805 grams||~950 grams|
II. EF 24mm f/2.8 IS USM (Photo 2) and EF 28mm f/2.8 IS USM (Photo 3)
These two wide-angle prime lenses were developed as the successors to the EF 24mm f/2.8 and EF 28 f/2.8 lenses. Beginning with image quality and image stabilization ready for the digital age, these lenses were designed to function and perform at a level far beyond their predecessors.
The EF 24mm f/2.8 IS USM and the EF 28mm f/2.8 IS USM pack improved peripheral image quality and provided more accurate, faster, and quieter AF performance as well as full-time manual focusing and other functions into a compact body only possible in a prime lens. The inclusion of an image stabilizer, in particular, provides more creative shooting possibilities at slow shutter speeds.
For users of APS-C sensor cameras, the lenses function as multifunctional standard lenses providing high quality images at equivalent focal lengths of 38mm and 45mm respectively.
The following sections describe the main features of the two lenses.
Feature 1 — World's first*1 wide-angle prime lenses with an image stabilizer
The two lenses' biggest advancement is their image stabilization mechanism, the first in the world to be used on wide-angle prime lenses. To incorporate the image stabilizer, we made wholesale modifications to the optical system of the EF 24mm f/2.8 and EF 28mm f/2.8 and employed a rear-focusing system so that the overall length does not change while focusing. Image stabilization is realized with a single lens element, placed after the diaphragm in the focusing lens group, that shifts to compensate for camera shake (figures 4 and 5).
A small actuator drives the image stabilizer unit, which moves on rolling balls to keep friction to a minimum. The actuator's control algorithm is optimized to suit the specific characteristics of the image stabilizer unit. With image stabilization on, the lenses can deliver a stabilization gain of about four f-stops in shutter speed.*2 All told, the lenses provide excellent image stabilization at shutter speeds as long as half a second in a body as nearly as compact the previous models'.
The image stabilizer also has a function that distinguishes between panning and normal shooting from a gyro output signal and automatically adjusts the image stabilization mode accordingly.
*1 As of February 2012 according to a Canon survey.
*2 Assuming that image stabilization generally reaches its effective limit at a shutter speed of about [1/focal length] seconds. Also, in certain conditions, depending on the tripod type or camera, there may be less blurring in the resulting photograph when the image stabilization function is off.
Feature 2 — Improved image quality and shorter minimum focusing distance
In both lenses, the rearmost lens element is a GMo aspherical element that compensates for various aberrations. This GMo aspherical element also has the benefit of rendering images with even quality across the entire frame (figures 6 and 7).
Advanced simulation technology was used to optimize the lens coating, which provides excellent color balance as well as minimal flaring and ghosting that commonly occurs with digital cameras.
Furthermore, the two lenses feature shorter minimum focusing distances than their predecessors. The EF 24mm f/2.8 IS USM reduces the minimum focusing distance from the previous model's 0.25 meters to 0.20 meters and increases the maximum magnification ratio from 0.16x to 0.23x. Similarly, the EF 28mm f/2.8 IS USM reduces the minimum focusing distance from the previous model's 0.30 meters to 0.23 meters and increases the maximum magnification ratio from 0.13x to 0.20x.
In addition to employing the rear-focusing system mentioned above, the latest optical design technology was used to optimize the lens construction. This minimizes the drop off in image-rendering performance during close-up photography, thereby expanding the lenses' shooting possibilities over the previous models.
Feature 3 — Improved AF performance and full-time manual focusing
The ring USM that drives the focusing lens uses the same design as the ring USM on the EF 8–15mm f/4 fisheye USM lens. The lenses achieve faster autofocusing thanks to an optimized AF algorithm and a high-performance CPU borrowed from the EF 600mm f/4L IS II USM super telephoto lens and other lenses. Also included is full-time manual focusing, which lets the user adjust the focus manually after autofocusing while in the autofocus mode (in the one-shot AF mode). Furthermore, the focusing control and aperture control have been improved to meet the demands of movie shooting.
The concept of the exterior design was to provide a high-end feel for the lenses while prioritizing operability. Working from this concept, we formed the lens silhouette and molding for maximum operational comfort.
The lenses come with the EW-65B (Photo 5) hood. The hood's inner surface has been given a flocking treatment for excellent anti-reflective performance.
We encourage everyone to add the EF 24mm f/2.8 IS USM and the EF 28mm f/2.8 IS USM to their camera bag for casual snaps and for more comfortable shooting provided by the image stabilizer and excellent close-up performance.
|Model||EF 24mm f/2.8 IS USM||EF 24mm f/2.8|
|Lens construction||11 elements in 9 groups||10 elements in 10 groups|
|Aspherical lens elements||1||0|
|Aperture blades||7 (circular)||6|
|Min. focusing distance||0.2 m||0.25 m|
|Filter size||58 mm||58 mm|
|Max. diameter||68.4 mm||67.5 mm|
|Overall length||55.7 mm||48.5 mm|
|Weight||~280 grams||~270 grams|
|Model||EF 28mm f/2.8 IS USM||EF 28mm f/2.8|
|Lens construction||9 elements in 7 groups||5 elements in 5 groups|
|Aspherical lens elements||1||1|
|Aperture blades||7 (circular)||5|
|Min. focusing distance||0.23 m||0.3 m|
|Filter size||58 mm||52 mm|
|Max. diameter||68.4 mm||67.4 mm|
|Overall length||51.5 mm||42.5 mm|
|Weight||~260 grams||~185 grams|